Contrib Mineral Petrol (1991) 107 : 41-59 Contributions to Mineralogy and Petrology Springer-Verlag 1991 Partial melting of two amphibolites: contrasting experimental results under fluid-absent conditions Tracy Rushmer Department fuer Erdwissenschaften, ETH Zuerich, CH-8092, Switzerland Received December 15, 1989 / Accepted August 15, 1990 Abstract. A large portion of the lower continental crust may be amphibolitic in composition and without a free fluid phase. As a consequence, H20-undersaturated or fluid-absent melting of amphibolites may be responsible for the formation of some granites and migmatites pro- duced during major orogenic events. In an attempt to determine the systematics of melting under fluid-absent conditions, a series of piston-cylinder experiments was conducted on two natural amphibolites; one, a recta- alkali basalt (ABA) with a total water content of ~1 wt% contained in hornblende, and the other, a meta-island-arc tholeiite OAT) which has ~ 1 1.3 wt% water contained in hornblende, cummingtonite and bio- tite. The experimentally determined melting ranges of
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